Times-Picayune archiveThe second-biggest cause of accidents was stormwater and wastewater overflows, which resulted in 11.7 million gallons of pollutants -- all from Chalmette Refining in St. Bernard Parish, the study says.

As Louisiana enters the 2010 hurricane season worrying about the effects of tropical storms on the uncontrolled release of oil in the Gulf of Mexico, researchers released a survey showing that accidents during storms are responsible for a significant portion of air and water pollution at oil refineries in the state.

Researchers with the Louisiana Bucket Brigade surveyed releases between 2005 and 2008, and found storms were listed as the cause of 5 percent, or 110, of all oil refinery accidents between 2005 and 2008, based on information provided by the refineries to the state Department of Environmental Quality.

But in terms of the volume of material released, storms play a much larger role than that number suggests. The survey found storm-related accidents accounted for 24 percent, or 3.6 million pounds, of all air pollution and 64 percent, or 14.1 million gallons, of all water pollution from all accidents during those years. That was more than from any other accident cause.

The organization recommends a revamping of emergency procedures for the state's refineries, with a greater emphasis on preparing for power failures and on providing enough capacity to hold polluted wastewater and contaminated stormwater.

The study included accidents that occurred during Hurricanes Katrina and Rita in 2005, and Gustav and Ike in 2008. It also included accidents that occurred during rainstorms and as the result of lightning strikes.

"The most frequent cause of accidents during storms was improper start-up and shutdown procedures," resulting in the release of 2.6 million pounds of air pollution, the report said. The second-biggest cause was stormwater and wastewater overflows, which resulted in 11.7 million gallons of pollutants -- all from Chalmette Refining in St. Bernard Parish, which dumped the polluted water into Lake Borgne on Aug. 31, 2008, just before Hurricane Gustav made landfall.

Other accidents resulted from power failures, equipment failures and human error, according to the company reports.

ExxonMobil's Baton Rouge refinery also released 1.2 million pounds of air pollutants Aug. 31, 2008, as it conducted an emergency shutdown in advance of Gustav.

"A federal investigation found that by not properly following their hurricane procedures, ExxonMobil wrongfully endangered its workers," the report said, resulting in a $5,000 fine against the company.